var row = 28;
var col = 16;
var announcement = 6;
var size = 20;
var isOver = false;
var shapes = ("0,1,1,1,2,1,3,1;1,0,1,1,1,2,2,2;2,0,2,1,2,2,1,2;0,1,1,1,1,2,2,2;1,2,2,2,2,1,3,1;1,1,2,1,1,2,2,2;0,2,1,2,1,1,2,2").split(";");
var tetris;
var container;
function createElm(tag, css) {
	var elm = document.createElement(tag);
	elm.className = css;
	document.body.appendChild(elm);
	return elm;
}


function Tetris(css, x, y, shape) {
// 创建4个div用来组合出各种方块
var myCss = css ? css : "c";
this.divs = [createElm("div", myCss), createElm("div", myCss), createElm("div", myCss), createElm("div", myCss)];
if(!shape) {
	this.divs2 = [createElm("div", myCss), createElm("div", myCss), createElm("div", myCss), createElm("div", myCss)];
	this.score = createElm("div", "g");
	this.score.style.top = 10 * size + "px";
	this.score.style.left = (col - -1) * size + "px";
	this.score.innerHTML = "score:0";
}
this.container = null;
this.refresh = function() {
	this.x = (typeof(x) != 'undefined') ? x : 3;
	this.y = (typeof(y) != 'undefined') ? y : 0;
// 如果有传参，优先使用参数的，如果有预告，优先使用预告，都没有就自己生成
if(shape)
	this.shape = shape;
else if(this.shape2)
	this.shape = this.shape2;
else
	this.shape = shape ? shape : shapes[Math.floor((Math.random() * shapes.length - 0.000000001))].split(",");
this.shape2 = shapes[Math.floor((Math.random() * shapes.length - 0.000000001))].split(",");
if(this.container && !this.container.check(this.x, this.y, this.shape)) {
	isOver = true;
	alert("游戏结束");
} else {
	this.show();
	this.showScore();
	this.showAnnouncement();
}
}
// 显示方块
this.show = function() {
	for(var i in this.divs) {
this.divs[i].style.top = (this.shape[i * 2 + 1] - -this.y) * size + "px";//顶部中间开始
this.divs[i].style.left = (this.shape[i * 2] - -this.x) * size + "px";
}
}
// 显示预告
this.showAnnouncement = function() {
	for(var i in this.divs2) {
this.divs2[i].style.top = (this.shape2[i * 2 + 1] - -1) * size + "px";//定位在显示区
this.divs2[i].style.left = (this.shape2[i * 2] - -1 - -col) * size + "px";
}
}
// 显示分数
this.showScore = function() {
	if(this.container && this.score) {
		this.score.innerHTML = "score:" + this.container.score;
	}
}
// 水平移动方块的位置
this.hMove = function(step) {
	if(this.container.check(this.x - -step, this.y, this.shape)) {
		this.x += step;
		this.show();
	}
}
// 垂直移动方块位置
this.vMove = function(step) {
	if(this.container.check(this.x, this.y - -step, this.shape)) {
		this.y += step;
		this.show();
	} else {
		this.container.fixShape(this.x, this.y, this.shape);
		this.container.findFull();
		this.refresh();
	}
}
// 旋转方块
this.rotate = function() {
	var newShape = [this.shape[1], 3 - this.shape[0], this.shape[3], 3 - this.shape[2], this.shape[5], 3 - this.shape[4], this.shape[7], 3 - this.shape[6]];
	if(this.container.check(this.x, this.y, newShape)) {
		this.shape = newShape;
		this.show();
	}
}
this.refresh();
}


function Container() {
	this.init = function() {
// 绘制方块所在区域
var bgDiv = createElm("div", "f");
bgDiv.style.width = size * col + "px";
bgDiv.style.height = size * row + "px";
// 绘制预告所在区域
var bgDiv = createElm("div", "e");
bgDiv.style.left = size * col + "px";
bgDiv.style.width = size * announcement + "px";
bgDiv.style.height = size * row + "px";
// 清空积分
this.score = 0;
}
this.check = function(x, y, shape) {
// 检查边界越界
var flag = false;
var leftmost = col;
var rightmost = 0;
var undermost = 0;
for(var i = 0; i < 8; i += 2) {
// 记录最左边水平坐标
if(shape[i] < leftmost)
	leftmost = shape[i];
// 记录最右边水平坐标
if(shape[i] > rightmost)
	rightmost = shape[i];
// 记录最下边垂直坐标
if(shape[i + 1] > undermost)
	undermost = shape[i + 1];
// 判断是否碰撞
if(this[(shape[i + 1] - -y) * 100 - -(shape[i] - -x)])
	flag = true;
}
// 判断是否到达极限高度
for(var m = 0; m < 3; m++)
	for(var n = 0; n < col; n++)
		if(this[m * 100 + n])
			flag = true;
		if((rightmost - -x + 1) > col || (leftmost - -x) < 0 || (undermost - -y + 1) > row || flag)
			return false;
		return true;
	}
// 用灰色方块替换红色方块，并在容器中记录灰色方块的位置
this.fixShape = function(x, y, shape) {
	var t = new Tetris("d", x, y, shape);
	for(var i = 0; i < 8; i += 2)
		this[(shape[i + 1] - -y) * 100 - -(shape[i] - -x)] = t.divs[i / 2];
}
// 遍历整个容器，判断是否可以消除
this.findFull = function() {
	var s = 0;
	for(var m = 0; m < row; m++) {
		var count = 0;
		for(var n = 0; n < col; n++)
			if(this[m * 100 + n])
				count++;
			if(count == col) {
				s++;
				this.removeLine(m);
			}
		}
		this.score -= -this.calScore(s);
	}
	this.calScore = function(s) {
		if(s != 0)
			return s - -this.calScore(s - 1)
		else
			return 0;
	}
// 消除指定一行方块
this.removeLine = function(row) {
// 移除一行方块
for(var n = 0; n < col; n++)
	document.body.removeChild(this[row * 100 + n]);
// 把所消除行上面所有的方块下移一行
for(var i = row; i > 0; i--) {
	for(var j = 0; j < col; j++) {
this[i * 100 - -j] = this[(i - 1) * 100 - -j]//数组中 消除行上的所有元素逐行下移 （等同于在数组改变位置）
if(this[i * 100 - -j])//如果此下标有元素 让其定位到要显示的位置
	this[i * 100 - -j].style.top = i * size + "px";
}
}
}
}


function init() {
	container = new Container();
	container.init();
	tetris = new Tetris();
	tetris.container = container;
	document.onkeydown = function(e) {
		if(isOver) return;
		var e = window.event ? window.event : e;
		switch(e.keyCode) {
case 38: //up
tetris.rotate();
break;
case 40: //down
tetris.vMove(1);
break;
case 37: //left
tetris.hMove(-1);
break;
case 39: //right
tetris.hMove(1);
break;
}
}
setInterval("if(!isOver) tetris.vMove(1)", 500);
}